[Reviewer Guidance] Capture reviewer self-report on reference materials used

[aashish24]

Background:
We cannot control reference materials, but we should ask and record what was used.

Requirements:
Add a short self-report prompt (ideally once per dataset or session):
Used reference materials? (Yes/No)
If yes, what kind? (free text or categories)

Acceptance criteria:
Reviewer can submit self-report.
Stored and exportable for analysis.